grade) trial began in November 2010, presided over by Judges Claudio Pratillo Hellmann and Massimo Zanetti. A court-ordered review of the contested DNA evidence by independent experts noted numerous basic errors in the gathering and analysis of the evidence, and concluded that no evidential trace of Kercher's DNA had been found on the alleged murder weapon. Although the review confirmed the DNA fragments on the bra clasp included some from Sollecito, an expert testified that the context strongly suggested contamination. On 3 October 2011, Knox and Sollecito were acquitted. A ruling that proof was insufficient, similar to the verdict of not proven, was available to the court, but the court acquitted Knox and Sollecito completely. The conviction of Knox on a charge of slander of Patrick Lumumba was upheld, and the original one-year sentence was increased to three years and eleven days' imprisonment. In their official report on the court's decision to overturn the convictions, the appeal trial judges wrote that the verdict of guilty at the original trial "was not corroborated by any objective element of evidence". Describing the police interviews of Knox as of "obsessive duration", the judges said that the statements she made incriminating herself and Lumumba during interrogation were evidence of her confusion while under "great psychological pressure". The judges further noted that a tramp who had testified to seeing Sollecito and Knox in the Piazza Grimana on the night of the murder was a heroin addict; that Massei, the judge at the 2009 trial, had used the word "probably" 39 times in his report; and that no evidence existed of any phone calls or texts between Knox or Sollecito, and Guede. New trial Following a successful prosecution request, a rehearing of Knox and Sollecito's second-level trial was held. The only new evidence came from the court-ordered analysis of a previously unexamined sample of the blade of Sollecito's kitchen knife, which the prosecution had alleged was the murder weapon. When the unexamined sample was tested by court-appointed experts for the new appeal trial, no DNA belonging to Kercher was found. Despite the negative result for the prosecution case, the court returned verdicts of guilty against the defendants, who both appealed. Acquittal of murder charge On 27 March 2015, Italy's highest court, the Court of Cassation, ruled that Knox and Sollecito were innocent of murder, thereby definitively ending the case. Rather than merely declaring that errors occurred